| In the Mohenjodaro excavates of Indus civilization, wheat grains, estimated
to be as old as 5,000 years before the present, were found. I saw them in
the museum on my visit in 1950 (ref. figure on cover i). They are probably
T. sphaerococcum (6x). If we assume that the 6x wheats originated from the 4x wheats under cultivation, then they originated at a later time, a time when the 4x wheats had a wide distribution. Since cytogenetically the 6x wheats seem to have a single origin - from 4x wheats x Aegilops squarrosa - we might conclude that they had a single geographical point of origin not necessarily the same as the point of origin of the 4x wheats. KIHARA (1975) stated: "As for the place of origination, we think Azerbaijan and its adjacent region might be the candidates. - We think that the present day 6x wheats may have been arisen in ancient farmers field as the hybrids between cultivated emmer and Ae. squarrosa and they were preserved.", and further," The problem is the time of cultivation of wheat. This cannot be estimated biologically at present. However, archaeological excavations in Iraq and Afghanistan yielded carbonated grains of hexaploid wheat. So at least 6,000 to 8,000 years ago wheat was cultivated in this area. So we might be justified in estimating the time of origination as roughly 8 to 10 thousand years ago." In general, the place of origin of the alloploid crops is to be found where the ancestral species occurred, but it is difficult or almost impossible to point out precisely where the diploid ancestors were domesticated. HARLAN (1970) suggested that, "the general locale for wheat and barley domestication seems to be in or near the oak woodland belts in an arc through the hilly country surrounding, the Syrian-Mesopotamian plains. The arc stretches from Kuzestan in Iran through the Western Zagros, the Tauros of Turkey and down the Antilebanon to the Southern Jordan highlands near the Dead Sea rift." We in 1970, observed the same geobotanical situations where, in many places, wild diploid wheat, Aegilops speltoides and wild tetraploid wheat occurred in association. Dispersion of Wheats From the presumed place of origin, cultivated wheats dispersed west- and east-wards. The west-bound dispersion took two pathways, one through the European continent and the other along the Mediterranean Sea. The former brought forth the differentiation of the varieties of 6x wheats, and the latter the differentiation of 4x wheats. "In Italy the greatest interest attaches to the hybridization work of the Institute headed by the eminent breeder STRAMPELLI, who created a number of excellent varieties which today are widely cultivated, not only in Italy but also in neighboring countries. Particularly outstanding is his variety Ardito. From Italy this variety has centered in Argentina, Chile, and France, and today occupies millions of hectares. Its one serious defect is its shattering. Its pedigree includes an English wheat of the squarehead type and an Italian local form of the Rieti type, while a decisive role in Ardito's formation was played by the Japanese variety Akagomughi, which has an oriental appearance, is low growing, with bright yellow color, and shatters easily, a characteristic of Japanese wheats. The role of Japanese varieties is an outstanding feature of recent Italian breeding." (VAVILOV, 1951). |
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